The present invention relates to an assist assembly for reducing the effort required by an operator in rotating a cab structure on a machine between selected positions.
The invention may be used in connection with a front end loader of the type having a material handling bucket supported for pivotal movement about a transverse axis on the forward end of a boom structure. The conventional front end loader disclosed herein includes an elongated body having an engine compartment adjacent the rear end thereof and an operator's compartment mounted on the body. In machines of this type, usually some form of cab structure is provided for enclosing the operator's compartment. A problem arises because the cab structure prevents free access into the internal working parts of the machine for maintenance and repair work.
To overcome this problem, the cab structure may be rotatably attached to the loader frame for permitting rotational movement of the cab structure about a horizontal axis that is transverse to the longitudinal axis of the machine. The cab structure may then be rotated to an out-of-the-way position which will allow the operator access into the machine for maintenance or repair work. However, because of the size and weight of the cab structure, there is a need for a mechanism that will mechanically assist the operator in moving the cab structure to an out-of-the-way position and further assist the operator when he moves the cab structure back to its normally closed position.
During the rotational movement of the cab structure, its center of gravity passes through a point directly above its transverse rotational axis. Thus, it is desired that the assist mechanism help the operator in rotating the weight of the cab structure up to that point and then dampen or retard the movement of the cab structure until it reaches a stop position. Further, the mechanism should provide assistance to the operator when the cab structure is being rotated in either direction.
Thus, it is an object of the present invention to provide an assist assembly for reducing the work required by an operator in moving a rotatable cab structure between its extreme stop positions. The assist assembly of the present invention helps the operator in rotating the cab structure until its center of gravity moves to a point directly above the rotational axis for the cab structure and then dampens the movement of the cab structure until it reaches a stop position. The mechanical advantage provided by the assist assembly is the same when the cab structure is rotated in either direction.